#demo1{ 
    position: relative;       
}
#demo1 .img_list{overflow: hidden; position: relative; height:100vh;}
/* 根据图片的张数来设定ul的宽度 */
.img_list ul{ width: 3500px; position: absolute; height:auto; left: 0px;}
.img_list li{ float: left; width: 1920px; height:100vh;}
.img_list img{ width: 100%; height: auto;}

/* 图片对应的按钮样式 */
.btn_list ul{ position: absolute; right: 20px; bottom: 35px; }
.btn_list li{ float: left; margin-right: 10px; color: #999; border: 1px solid #ccc; background-repeat:no-repeat; background-position:center;}
.btn_list li:hover,.btn_list li.on{ cursor: pointer; border: 1px solid #E204A4;}
.btn_list li img{ width: 30px; height: 15px; display: block;}
/* 左右点击的按钮样式 */
#demo1 .toLeft,#demo1 .toRight{
    display: none;
    position: absolute;
    width: 20px;
    height: 30px;    
    top: 110px;    
    background: url(image/zbbg_24.png) no-repeat 0 -150px;
}

/* 图片对应的说明*/
.img_intro{
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 25px;
}
.img_intro .img_intro_bg,.img_intro .text{
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
}
.img_intro .img_intro_bg{
    background: #000;    
    opacity: .3;
    z-index: 999;
}
.img_intro .text{
    padding: 5px 10px;
    z-index: 1000;
    color: #999;
}
#demo1 .toLeft{
    left: -40px;
    color: #999;
}
#demo1 .toRight{
    right: -40px;
    color: #999;
    background-position: -50px -150px;
}